Example of plated steel sheets most commonly recognized as having a good corrosion resistance are galvanized-type steel sheets. Such galvanized-type steel sheets are used in various manufacturing industries including the fields of automobiles, home electric appliances and building materials and most of them are used, after being painted, from the viewpoint of corrosion resistance and designability.
In order to improve the corrosion resistance of such galvanized-type steel sheets, it is possible to use Zn—Al—Mg—Si hot dip plated steel sheets as described in Japanese Patent No. 3179446. Further, Japanese Patent Publication No. 2000-064061 describes that a painted steel sheet more excellent in corrosion resistance can be obtained by adding one or more elements of Ca, Be, Ti, Cu, Ni, Co, Cr and Mn to such a proposed Zn—Al—Mg—Si hot dip plated steel sheet. Furthermore, Japanese Patent Publication No. 2001-295015 describes the fact that a surface appearance can be improved by adding Ti, B and Si to a Zn—Al—Mg hot dip plated steel sheet.
However, with the above-described conventional and other known plated steel sheets, sufficient corrosion resistance and paint coat image clarity may not be secured, e.g., in the case where they are used after being processed and painted.